The Gatwick Gusher has produced the highest flow rates of any onshore wildcat well in the UK, matching the kind of levels normally seen in the North Sea, its majority owner UK Oil & Gas said.

The exploration company said it had completed its final test at Horse Hill, just north of Gatwick Airport, and that the aggregate flow from three layers of oil-bearing rock had been 1,688 barrels per day.

“We are delighted, therefore, that this discovery has the serious prospect of being a meaningful addition to the UK’s own supply of oil in a period where North Sea production is declining more rapidly than expected.”

He said that the final tests, from the Portland sandstone level, had actually been limited because they hit the well pump’s maximum capacity limit. He also said that planned future drilling horizontally rather than just vertically could also significantly increase the rate of flow.

UKOG said it had commissioned Nutech and Xodus, oil engineering consultants, to provide estimates of how much oil may be recoverable from the reservoirs. Previous studies have suggested that there are reserves of around 10 billion barrels under Horse Hill.